| My Second Brand Ltd | Information & communication | 2024 |
| Mycardirect Ltd | Administrative & support | 2017 |
| Mycomarketing Limited | Wholesale & retail | 2000 |
| Myofitness Ltd | Wholesale & retail | 2025 |
| Myra Compliance Ltd | Information & communication | 2025 |
| Mysoulway Ltd | Administrative & support | 2021 |
| Mythiccorp Ltd | Wholesale & retail | 2020 |
| Myton Drive Limited | Real estate | 2022 |
| N.L Management Group Ltd | Financial services | 2026 |
| Naidu Infotech Limited | Wholesale & retail | 2025 |
| Nanny Spoon's Cakery Ltd | Manufacturing | 2022 |
| Narcolepsy UK | Other services | 2011 |
| Nathan Smith Electrical Services Limited | Manufacturing | 2016 |
| Natteye Limited | Other services | 2019 |
| Natural Grill Company Limited | Manufacturing | 2016 |
| Naturhof Weixler Ltd | Extraterritorial | 2021 |
| Naughty Pizza International Ltd | Hospitality | 2023 |
| Navigate International HR Consultants Ltd | Administrative & support | 2025 |
| Nawab Express Limited | Hospitality | 2026 |
| Nawab Lounge Limited | Hospitality | 2025 |
| NB Business Coaching Ltd | Professional & scientific | 2018 |
| NBR Property Invest Ltd | Real estate | 2025 |
| NC Marketing Services Ltd | Administrative & support | 2020 |
| Neater Cellars Limited | Other services | 2010 |
| Necly Company Ltd | Transport & logistics | 2019 |
| Neddy Ltd. | Real estate | 2013 |
| NEG Services (ST. Neots) Limited | Wholesale & retail | 2013 |
| Nelbrooke Developments Ltd. | Administrative & support | 2009 |
| Nelson Feast Limited | Hospitality | 2021 |
| Nemac Construction Ltd | Construction | 2019 |
| Neogi Family Network Ltd | Health & social care | 2018 |
| Neolytix Ltd | Information & communication | 2025 |
| Neosphinx Ltd | Information & communication | 2026 |
| Neotailor Ltd | Wholesale & retail | 2019 |
| Nestpal Ltd | Information & communication | 2026 |
| Neuroinclusive Link Limited | Public administration | 2024 |
| Neutrino Energy Limited | Manufacturing | 2021 |
| Never BEE Cleaner Ltd | Administrative & support | 2023 |
| Never Settle Physiques Limited | Health & social care | 2023 |
| New Bodrum Kitchen Ltd | Hospitality | 2024 |
| New Bodrum Ltd | Hospitality | 2026 |
| New Energy Marketing Limited | Professional & scientific | 2014 |
| New Layer Ltd | Information & communication | 2025 |
| New Season Property Investments Ltd | Real estate | 2021 |
| New Street Properties North Limited | Real estate | 2025 |
| Newmen Ltd. | Wholesale & retail | 2015 |
| Newtown Maintenance Ltd | Households | 2026 |
| Nexito Ltd | Administrative & support | 2014 |
| Nick Walker Limited | Administrative & support | 2011 |
| Nigel Saunders.Tv Ltd | Information & communication | 2010 |
| Nimbuspoint Consulting Limited | Professional & scientific | 2011 |
| NJM Lifting Ltd | Administrative & support | 2020 |
| NJS Developments Limited | Real estate | 2006 |
| NO Friends Films Ltd | Information & communication | 2023 |
| Noktop Ltd | Other services | 2018 |
| Nordic Noir Ltd | Construction | 2015 |
| North Direct Ltd | Wholesale & retail | 2015 |
| Northrop Heating Limited | Construction | 2003 |
| Norwich Laboratories Limited | Professional & scientific | 2025 |
| Notar Ltd | Other services | 2018 |
| Nova Amenities Ltd | Wholesale & retail | 2019 |
| NP Tennis & Racket Stringing Limited | Arts & recreation | 2015 |
| NS Communications Ltd | Professional & scientific | 2023 |
| Nunicorn Properties Limited | Real estate | 2021 |
| Nutrasulin Ltd. | Manufacturing | 2016 |
| Nutriclinic Ltd | Health & social care | 2021 |
| O'Shea SKN Limited | Wholesale & retail | 2023 |
| Oakford Homes (Bewick) Ltd | Construction | 2018 |
| Oakford Homes (West Sussex) LLP | | 2009 |
| Oakingtons Clinic Ltd | Health & social care | 2016 |
| Oakridge Accounting & Advisory Ltd | Administrative & support | 2022 |
| Oaoa Track Limited | Other services | 2015 |
| Oast Enterprises Ltd | Administrative & support | 2014 |
| Obrassa Ltd | Wholesale & retail | 2025 |
| Ocelot Enterprises Limited | Wholesale & retail | 2014 |
| Oculus Mundi Capital Ltd | Professional & scientific | 2025 |
| Ofetsai Ltd | Information & communication | 2025 |
| Office Hours Beauty Ltd | Wholesale & retail | 2026 |
| Official Cuts MO Ltd | Other services | 2023 |
| Offord Container Converters Limited | Construction | 2014 |
| Offord Distribution Limited | Transport & logistics | 2013 |
| Offord Holdings Limited | Financial services | 2025 |
| Offord Property Limited | Real estate | 2025 |
| Offord Psychology Services Limited | Health & social care | 2016 |
| Old Manor Farm (Yelling) Limited | Professional & scientific | 1995 |
| Old Red Barbers Limited | Other services | 2016 |
| Old School Property Developments Limited | Construction | 2021 |
| Olgun Properties Ltd | Real estate | 2024 |
| Olive Branch Delicacies Ltd | Hospitality | 2025 |
| Olive Communications Ltd | Professional & scientific | 2025 |
| Olive Grove Book-Keeping and Accounting Services Ltd | Professional & scientific | 2025 |
| Olive Grove Payroll and Administration Services Ltd | Professional & scientific | 2025 |
| Olympus Limousine Ltd | Transport & logistics | 2025 |
| Omak Group Limited | Construction | 2017 |
| Omra Funding and Administration Limited | Financial services | 2023 |
| ON Action Stunts Ltd | Arts & recreation | 2024 |
| ON Site Servicing Limited | Wholesale & retail | 2015 |
| One Blue Sky Ltd | Information & communication | 2011 |
| One Giant Leap Ltd | Professional & scientific | 2022 |
| One OFF Studio Ltd | Construction | 2019 |